Patent GB-1017626-A (GB)
Title: Manual and automatic change-speed transmission
IPC: F16H47/08
Filed: 1963-04-17
Abstract: 1,017,626. Change-speed control. BORG-WARNER CORPORATION. April 17, 1963 [April 23, 1962], No. 15192/63. Heading F2D. Three valves in a motor car &c. change-speed gear hydraulic control circuit are arranged so that the first valve, a manual ratio-range selector, when in its first position causes the two other valves, a 1-2 shift valve and a 2-3 shift valve, to be hydraulically locked in their low-speed positions; when in its second position locks the 1-2 shift valve in its second ratio position, but retains the 2-3 shift valve locked in its low speed position, and when in its third position, releases both the 1-2 and the 2-3 shift valves. Gearing.-The gearing is similar to that disclosed in Specification 912,399 (Group XXIV), and comprises an hydrodynamic torque converter 31 driving to a first input sun gear, a second sun gear, intermeshing planet pinions on a carrier, and an output ring gear. A front clutch 32, a rear clutch 33, a front brake 34 and a rear brake 35 are selectively engaged to provide two reduced ratios, direct drive and reverse. Pressure regulation.-Input and output driven pumps 100, 101, in circuit with one-way valves 134, 131, supply liquid under pressure from a sump 115 to a main regulator valve 107 and a main pipe 130. The overspill from the main regulator valve 107 is fed to the torque converter 31, the pressure in the torque converter being determined by a second regulator valve 108. The two regulator valves 107, 108 are adjusted by compensator pressure, which increases with increasing car speed, and decreases with increasing throttle (TV) pressure. Increasing compensator pressure reduces main pressure 130, and also reduces torque converter pressure, and vice versa. Thus the pressure engaging the various clutches &c. varies with the torque to be transmitted. Governor pressure.-An output driven governor 114, connected to main pressure 130 through a manual ratio-range selector valve 102 in all its forward settings, meters output-speeddependent governor pressure to a pipe 229. Throttle valves.-The car accelerator pedal is mechanically connected to a downshift valve 103 spring-connected to a throttle valve 104 metering main pressure as throttle-variable (TV) pressure in a pipe 204. TV pressure 204 is fed to a TV modulator valve 106 which limits increasing TV pressure in a pipe 227 to a predetermined maximum. Compensator valve.-A compensator valve 105 regulates main pressure 130 to a pipe 226 connected to the pressure regulating valves 107, 108, which then function as described above. The compensator valve 105 is acted upon by the opposed influences of TV modulator pressure 227 and governor pressure 229. Ratio-range selector-position 1, low hold.- Regulated main pressure 130 is admitted through the ratio-range selector valve 102 to pipes 243, 244, 289. The pipe 244 feeds the front clutch 32, and the governor 114. The pipe 289 feeds a 1-2 shift valve 112, which is accordingly opened, and hydraulically locked in its first speed position by the action of pressure on differential area lands. The pipe 243 feeds the release cavity of a double-acting servo applying the front brake 34, and also feeds a range control valve 113. This latter is so moved that liquid pressure is admitted through a pipe 275 to a 2-3 shift valve 111 and to the downshift valve 103. The 2-3 shift valve 111 is now hydraulically locked in its second speed position by the action of liquid pressure on differential area lands. The downshift valve 103 transmits liquid under pressure through a pipe 274 to the 2-3 shift valve 111 to assist the hydraulic locking. The pipe 243 feeds through the 1-2 shift valve 112 and a pipe 334 to a time-delay valve 109, and thence through a pipe 311, the 2-3 shift valve 111, a pipe 331, the delay valve 109 and a pipe 309 to the release cavity of the servo for the brake 34. Thus the front brake 34 is held disengaged. The pipe 309 also feeds a transition valve 110, which is opened so that the pipe 311 feeds through a pipe 310 to the servo for the front brake 35. First ratio is now established and the gear remains in this condition until the ratio range selector is moved to another position. Ratio-range selector-position 2, intermediate hold.-Main pressure 130 is now admitted to the pipes 243, 244, as before, but the pipe 289 is vented to sump. As there is now no pressure in the pipe 289, there is no locking pressure on the 1-2 shift valve 112. The piston of the 1-2 shift valve 112 is now moved by spring bias and by governor pressure 229 to its second speed position. However, the 2-3 shift valve 111 is still held hydraulically locked in its second speed position. The 1-2 shift valve 112 shutsoff the pipes 334, 331 and 311. The doubleacting servo for the front brake 34 thus engages this brake. At the same time, the servo for the rear brake 35 is vented through the pipe 310, the transition valve 110 and a bleed port to sump. Second ratio is thus established. No " kick-down " shift from second ratio can be obtained with this setting. Ratio-range selector-D position, drive range.- Main pressure 130 is admitted also to a pipe 300 and thence to a range control valve 113, which is conditioned to shut-off the pipe 275 from the pipe 243, so that locking pressure on the 2-3 shift valve 111 is released. With increasing governor pressure 229 and decreasing TV pressure 204, the 2-3 shift valve 111 moves to its third speed position. The 2-3 shift valve 111 is also acted upon by spring bias, and by a modulated TV pressure provided by a plug valve which it incorporates. When the 2-3 shift valve 111 has moved to its third speed position, main pressure 130 in the pipe 244 is connected to a pipe 273 and thence to the servo engaging the rear clutch 33. Liquid pressure is also fed through the pipes 331, 309 to the release cavity of the servo applying the front brake 34. The planetary gearing is now locked-up to give direct drive. If the motor car coasts to rest with released accelerator pedal, direct drive having been established in the gearing, the 2-3 shift valve 111 is returned to its low-speed position. The rear clutch servo is vented, and the front brake band 34 re-engaged to establish second speed. TV pressure 204 is reduced, since the accelerator pedal has been released, and allows the time-delay valve 109 to be so conditioned as to introduce a restriction 332 into the vent path from the rear clutch servo, and thus delay release of the rear clutch 33. There is accordingly overlap with the engagement of the front brake band, to obtain a cushioned down-shift. On kickdown of the accelerator pedal while direct drive is still established in the gearing, the downshift valve 103 connects main pressure 130 to the pipe 274 and the 2-3 shift valve 111. The latter is now moved to its second speed position, and second ratio is established. TV pressure 204 is sufficient to shift the timedelay valve 109 so that the restriction 332 is no longer operative. A quick ratio shift is therefore obtained. Manual downshifts.-Movement of the ratiorange selector valve 102 from D position first to position 2 and then to position 1 effects downshifts, except when the car speed is too high. Downshifts are then prevented by governor pressure 229 acting on the 2-3 shift valve 111 and the 1-2 shift valve 112, holding these valves in their high-speed positions. Ratio-range selector-reverse position.-Main pressure 130 is admitted through the ratiorange selector valve 102 to the pipes 243, 289 and also to a pipe 245. The pressure in the pipe 243 engages the front brake 34, and passes through the range control valve 113 to the 2-3 shift valve 111, which it locks in its low-speed position. Also, pressure in the pipe 243 passes through the 1-2 shift valve 112, locked in its low-speed position by the pressure in the pipe 289, to the pipe 334, the time-delay valve 109, the pipe 311, the 2-3 shift valve 111, the pipe 331, the time-delay valve 109 and the pipe 309 to the release chamber of the front brake servo. Liquid pressure is also supplied to the transition valve 110, and the pipe 311 is therefore connected to the pipe 310 to engage the rear brake 35. The pipe 245 supplies liquid to the TV modulator valve 106, the delay valve 109 and 2-3 shift valve 111. From the latter, liquid passes through the pipe 273 to the rear clutch 33. Reverse is now established. Compenator pressure is at a minimum so that regulated main pressure 130 is at a maximum.